Divided omental flap wrapping a multiple-branched graft replaced with an infected thoracic aortic aneurysm: A case report

Summary The omental flap is often used to fill the space around the artificial vascular graft as a network sheet to prevent artificial vascular infection. In this study, we report a case in which the omental flap was divided into three parts to fill the dead spaces around the multiple-branched graft, as well as to wrap the suture lines of the graft after graft replacement in a patient with an infected thoracic aorta. An 88-year-old woman was admitted to the hospital with fever and impaired consciousness. Computer tomography revealed an aortic arch aneurysm with enlargement. After emergency stent–graft interpolation and antibiotic treatment, an infected thoracic aortic aneurysm was removed, and a multiple-branched graft replacement of the upper arch was performed. After harvesting an omental flap based on the right gastroepiploic vessels, the omental flap was divided into three on the basis of the epiploic vessels. The middle part of the omental flap was used to fill the space around the lesser curvature of the arch and the distal anastomotic site, the accessory part was used to fill the space between the ascending aorta and the superior caval vein, and the right part was used to wrap the three cervical branches, separately. Fifteen months after surgery, the patient had recovered enough to resume work without any signs of inflammation.


a b s t r a c t
The omental flap is often used to fill the space around the artificial vascular graft as a network sheet to prevent artificial vascular infection. In this study, we report a case in which the omental flap was divided into three parts to fill the dead spaces around the multiple-branched graft, as well as to wrap the suture lines of the graft after graft replacement in a patient with an infected thoracic aorta.
An 88-year-old woman was admitted to the hospital with fever and impaired consciousness. Computer tomography revealed an aortic arch aneurysm with enlargement. After emergency stentgraft interpolation and antibiotic treatment, an infected thoracic aortic aneurysm was removed, and a multiple-branched graft replacement of the upper arch was performed. After harvesting an omental flap based on the right gastroepiploic vessels, the omental flap was divided into three on the basis of the epiploic vessels. The middle part of the omental flap was used to fill the space around the lesser curvature of the arch and the distal anastomotic site, the accessory part was used to fill the space between the ascending aorta and the superior caval vein, and the right part was used to wrap the three cervical branches, separately. Fifteen months after surgery, the patient had recovered enough to resume work without any signs of inflammation.

Introduction
Infected thoracic aortic aneurysms are relatively rare and difficult to treat. The aneurysm is often replaced by an artificial vascular graft, which is covered by an omental or muscle flap to prevent graft infection wherever possible. 1 The omental flap is often wrapped around the graft as a network sheet. 1 , 2 We herein report a case in which the omental flap was split into three parts based on the epiploic vessels to fill the complicated dead spaces and wrap the graft suture lines after graft replacement in a patient with an infected thoracic aorta.

Case presentation
An 88-year-old woman was admitted to the hospital with fever and impaired consciousness. Computer tomography revealed an aortic arch aneurysm with enlargement. Escherichia coli was cultured from the urine and blood, and ceftriaxone was administered. Emergency stent-graft interpolation was performed 1 week after hospitalization, and the infection subsided after treatment with piperacillin/tazobactam. Five weeks after admission, the infected thoracic aortic aneurysm was removed, and a multiplebranched graft replacement of the upper arch was performed ( Figure 1 A). We harvested the omental flap based on the right gastroepiploic vessels. As long as the gastroepiploic vessels were preserved, the omental flap was divided into three on the basis of the middle, right, and accessory epiploic ves-  ( Figure 1 B). The blood flow of the divided omental flap was confirmed with indocyanine green fluorescence imaging. The middle part was used to fill the space around the lesser curvature of the arch and the distal anastomotic site, the accessory part was used to fill the space between the ascending aorta and the superior caval vein ( Figure 1 C), and the right part was used to wrap the suture lines, especially at the three cervical branches ( Figure 1 D). The flap was secured with 4-0 absorbable monofilament sutures and covered the circumference of the graft. Within a few months after surgery, the patient experienced repeated pleural effusion and aspiration pneumonia. However, those symptoms had been improved with the 10-week application of antibiotics and the cardiac rehabilitation. 6 months after surgery, the patient had recovered enough to resume work without any signs of inflammation.

Discussion
The omental flap is often used in patients with mediastinitis or infected aortic aneurysm. Moreover, it is often used to fill dead spaces as a network sheet without division. Settembre et al. 3 demonstrated vascularization of the right gastroepiploic vessels, which supply several descending epiploic vessels. Zaha et al. 4 divided the flap into two parts for the purpose of breast reconstruction. Moreover, Suito et al. 5 divided the omental flap into three parts for the purpose of reconstructing a completely circumferentially degloved thumb. In this study, we divided the omental flap into three parts for the prevention of artificial graft infection.
Kim et al. 6 emphasized that aggressive intraoperative debridement with soft-tissue coverage results in a high rate of success in high-risk patients with mycotic aortic aneurysm. Aggressive debridement may lead to complicated dead spaces around the multiple-branched graft, especially the lesser curvature of the arch and between the ascending aorta and the superior caval vein, which is where we filled the dead spaces by dividing the omental flap in the present case.

Conclusion
The omental flap can be maximally utilized by confirming flap blood flow and dividing the flap into multiple parts as needed.

Funding
None.

Ethical approval
Not required.

Declaration of Competing Interest
None.